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Polymer-based dielectrics have attracted much attention in flexible electronics due to their excellent flexibility and dielectric and mechanical properties. However, the rational design of a nanofiller–polymer nanocomposite for improving dielectric and mechanical properties remains challenging. Herein, layered dielectric nanocomposites filled with high-κ Ca2Nb3O10 perovskite nanosheets were fabricated via shear-flow-induced alignment of nanosheets. The hierarchical structure and good dispersion of nanosheets endowed the layered nanocomposites with an outstanding modulus of 12.7 GPa and toughness of 1.8 MJ/m3. Meanwhile, the layered nanocomposites exhibited a high dielectric constant of 14.7, a low dielectric loss of 4.2%, and low leakage current density of <1 × 10–7 A/cm2. The layered dielectric nanocomposites designed in this work have broad application prospects in flexible electronics. [ABSTRACT FROM AUTHOR]

The production of high temperature and high pressure gas wells fluctuates with time, which makes the pressure in the string fluctuate obviously and affects the service security of tubing string. In this paper, a pressure fluctuation model of the complete production process (including well opening, production and shut-in) is established, which is suitable for the multiphase flow of gas well. The pressure fluctuation in the tubing string is simulated. Influence of different well depth and average production on the fluctuating pressure of gas well are analyzed. According to the research results, if the well opening time top is 50 s, a transient pressure fluctuation is generated at wellhead and drops gradually. After the production starts, a pressure fluctuation will occur at wellhead 10~15 s after top, which is small and attenuates quickly. Pressure increases quickly in the shut-in moment and reaches the peak at tsh. Although pressure increases gradually with the well depth, fluctuation flattens out. The hysteresis phenomenon in appearance of pressure wave becomes more and more obvious with the well depth. The greater the production of gas well, the greater the pressure fluctuation in tubing string during well opening and production, but the value may not be very high. During well shut-in, the greater the production, the greater the pressure fluctuation and the value. Amplitude, angular frequency and value of phase are in direct proportion to pressure fluctuation degree and valve radix is in inverse proportion to pressure, which means that the greater the valve radix, the smaller the pressure.

BACKGROUND In the kidney, 5-hydroxytryptamine (5-HT) and dopamine (DA) are formed by the same enzyme, l-aromatic amino acid decarboxylase, but act on renal function and glomerular structure in an opposite direction. The present study was designed to explore whether rates of renal production of 5-HT relative to that of DA are altered in patients with essential hypertension and microalbuminuria. METHODS We measured urinary levels of 5-HT and DA, reflecting renal production of 5-HT and DA as well as 24-hour ambulatory blood pressure and urinary albumin excretion in 82 consecutive untreated, essential hypertensives without overt proteinuria. RESULTS Urinary 5-HT excretion and the ratio of urinary 5-HT to DA were significantly higher in 22 patients with microalbuminuria than in the remaining patients with normoalbuminuria, although urinary DA levels did not differ between the groups. The 24-hour systolic and diastolic blood pressures were also higher in the microalbuminuric group than in the normoalbuminuric group. Multiple regression analysis revealed that urinary 5-HT excretion and 24-hour systolic blood pressure were independently associated with urinary albumin excretion. Furthermore, urinary 5-HT excretion was positively correlated with creatinine clearance as well as blood pressure but tended to be negatively correlated with fractional excretion of sodium. CONCLUSIONS Renal production of 5-HT is enhanced compared with that of DA in essential hypertensives with microalbuminuria. This imbalance may contribute to the genesis of hypertensive glomerular damage. [ABSTRACT FROM PUBLISHER]

We report herein a 27-year-old male case of inherited distal renal tubular acidosis complicated with renal diabetes insipidus, the symptoms of which were aggravated by the occurrence of diabetes mellitus. At 2 months after birth, he was diagnosed as having inherited distal renal tubular acidosis and thereafter supplementation of both potassium and alkali was started to treat his hypokalemia and metabolic acidosis. At the age of 4 years, calcification of the bilateral renal medulla was detected by computed tomography. Subsequently his urinary volume gradually increased and polyuria of approximately 4 L/day persisted. At the age of 27 years, he became fond of sugar-sweetened drinks and also often forgot to take the medicine. He was admitted to our hospital due to polyuria of more than 10 L day, muscle weakness and gait disturbance. Laboratory tests disclosed worsening of both hypokalemia and metabolic acidosis in addition to severe hyperglycemia. It seemed likely that occurrence of diabetes mellitus and cessation of medications can induce osmotic diuresis and aggravate hypokalemia and metabolic acidosis. Consequently, severe dehydration, hypokalemia-induced damage of his urinary concentration ability and enhancement of the renin angiotensin system occurred and thereby possibly worsened his hypokalemia and metabolic acidosis. As normalization of hyperglycemia and metabolic acidosis might have exacerbated hypokalemia further, dehydration and hypokalemia were treated first. Following intensive treatment, these abnormalities were improved, but polyuria persisted. Elevated plasma antidiuretic hormone (12.0 pg/mL) and deficit of renal responses to antidiuretic hormone suggested that the polyuria was attributable to the preexisting renal diabetes insipidus possibly caused by bilateral renal medulla calcification. Thiazide diuretic or nonsteroidal anti-inflammatory drugs were not effective for the treatment of diabetes insipidus in the present case.

A 55-year-old man was admitted to our hospital because of arthralgia, purpura, abdominal pain, melena and leg edema. Laboratory findings showed an increased serum creatinine level (2.4 mg/dL), hematuria and massive proteinuria (10.7 g/day). Renal biopsy revealed diffuse endocapillary proliferation and focal mesangial proliferation with IgA deposition predominantly in the glomerular capillary walls. Based on these findings, he was diagnosed as having Henoch-Schönlein purpura nephritis and steroid therapy was started. Following steroid therapy, his nephrotic state remained unchanged, although his renal function improved concomitantly with the disappearance of arthralgia, purpura and abdominal symptoms. Therefore, cyclosporine was added to the steroid therapy to enhance immunosuppression. However, melena recurred and anemia progressed. Endoscopy revealed multiple ulcers in the duodenum and jejunum, and clipping was performed at some bleeding sites. However, he died of hemorrhagic shock. The autopsy revealed that hemorrhagic lesions having cytomegalovirus infection spread widely in the stomach, duodenum and jejunum. Recurrence of gastrointestinal bleeding during the treatment of Henoch-Schönlein purpura nephritis is usually due to severe vasculitis or steroid ulcer. However, in patients receiving strong immunosuppressive therapy, cytomegalovirus infection needs to be considered as cause of gastrointestinal bleeding.